Contact printing apparatus



J. HRUBY CONTACT PRINTING APPARATUS Nov 7, 1967 3 Sheets-Sheet 1 5V1 HimFiled Jan.

Nov. 7, 1967 J. HRUBY CONTACT PRINTING APPARATUS a sheets-sheet 2 FiledJan. 20, 1966 m QZ QE at MS $6 fiwenicrr somsak m fig} Nov. 7, 1967HRUBY CONTACT PRINTING APPARATUS 3 Sheets-Sheet 5 Filed Jan. 20, 19661051 016 Wj ar www- United States Patent 3,351,752 CONTACT PRINTINGAPPARATUS Joseph Hruby, Deerfield, 11]., assignor to Addressograph-Multigraph Corporation, Mount Prospect, Ill., a corporation of DelawareFiled Jan. 20, 1966, Ser. No. 521,860 Claims. (Cl. 240-49) ABSTRACT OFTHE DISCLOSURE An exposure apparatus for making contact exposures of adiazo-type copy sheet through a translucent original by sliding the twosheets in superimposed relatlonship directly over the surface of thelamp envelope. A series of spaced apart continuous loop bands arestretched around three cylinders, one of which is a driven roller, withthe outside surface of the bands being partially Wrapped in a looparound the outside of the lamp envelope. Guide wheels acting against thesurface of the envelope keep it supported inside the loop and againstthe bands so that the envelope can be rotated about a fixed axis. Thelateral ends of the lamp are equipped with single terminals makingelectrical contact with spaced apart contactors so that electricalcontact is made during rotation obviating the need for commutating typedevices.

The present invention relates to contact printing apparatus and moreparticularly to apparatus for exposing a copy sheet in accordance with asuperimposed ongmal sheet by means of illumination provided by arotating light source.

The direct contact or diazo process of producing copies of translucentgraphic originals has achieved wide acceptance because of itsefficiency, low cost and speed. In carrying out this process, anoriginal sheet and a photosensitive copy sheet, or web, are superimposedand subjected to illumination in order to produce an exposure image onthe copy sheet. The completed copy results when the copy sheet isdeveloped by exposure to a developing gas, such as ammonia and watervapor.

A known type of contact printing apparatus for illuminating superimposedcopy and original sheets includes a rotating transparent drum enclosinga stationary lamp. Superimposed copy and original sheets are passedaround the drum, commonly by a drive belt arrangement, where they areilluminated by light passing through the drum. An advantage of thisarrangement is that the lamp is stationary, and no difficulty isencountered in establishing electrical connections to the lamp.

In an attempt to provide a simpler arrangement, and in order to bringthe light source closer to the superimposed sheets, it has been proposedthat the envelope of the lamp serve itself as the rotating drum. Indevices of this type, since the lamp is rotated, problems arise inmaking the necessary electrical connections to operate the lamp, andknown arrangements for making the necessary electrical connections torotating lamps are quite complex and inconvenient.

Accordingly, it is an object of the present invention to provideimproved contact printing apparatus in which the disadvantages of knownapparatus are avoided.

Another object is to provide improved apparatus of the type wherein arotating lamp is used to illuminate a copy sheet in accordance with anoriginal to be copied.

Yet another object of the invention is to provide improved apparatus forestablishing electrical connections with a rotating lamp.

Another object of the invention is to provide contact printing apparatusof the type using a rotating vapor ice lamp and including a novelarrangement for establishing an operating potential difference acrossthe lamp.

Still another object of the invention is to provide contact printingapparatus including a novel arrangement for starting a vapor lampassociated with the apparatus either when the lamp is stationary in anyangular position, or when the lamp is rotating.

A further object of the invention is to provide an improved arrangementfor discontinuing the rotation of the lamp while the lamp is started.

In brief, a contact printing machine embodying the features of thepresent invention may comprise a supporting and easing structure withinwhich is rotatably mounted a fluorescent lamp having a cylindricalenvelope over which superimposed copy and original sheets are passed inorder to illuminate the sheets. In order fully to support and to rotatethe lamp, the machine includes several rollers supporting a plurality ofendless belts. The envelope of the lamp is arranged in a loop of thebelts included between two adjacent rollers, and one or more of therollers is driven at a desired speed by means of a drive system in orderto move the belts and thereby rotate the lamp.

In accordance with a feature of the invention, the machine includesnovel means for establishing the electrical connections for operatingthe rotating lamp. Within the envelope at each end of the lamp there isdisposed an electrode connected between a pair of terminals leadingoutside of the envelope. Each end of the envelope is provided with aconductive metal end cap electrically connected to a first of theterminals and isolated from the second of the terminals. In order tofacilitate the establishment of an operating potential differencebetween the electrodes, each end of the lamp is provided with aconnector frictionally engageable with the pair of terminals and therebyheld in place for rotation with the lamp. Each connector includes acontact member disposed substantially along the axis of the lamp, thecontact member being electrically connected to the second of the twolamp terminals. The connector includes insulating portions for isolatingthe first of the two terminals from the contact member.

In order to establish electrical connection to the electrodes, themachine includes a pair of resilient contactors located one near eachend of the lamp. The contactors are resiliently biased against thecontact members of the connectors, thereby establishing a firstelectrical connection with the electrodes at each end of the lamp. Themachine also includes a conventional power supply for operating thelamp, the power supply being connected to the two resilient contactors,whereby an operating potential difference is established within the lampbetween the two electrodes.

In accordance with another feature of the invention, the machineincludes a novel arrangement for starting the fluorescent lamp. Thus themetal end caps at each end of the lamp include cylindrical portionsoverlying the lamp envelope for a distance, the cylindrical portionsserving as contact bands. A starting bar is mounted in the machine formovement between an inactive position and a lamp starting position.Conveniently, an Operating handle may be connected to the starting barto move the bar to the starting position when it is desired to begin acontact printing operation. Supported along the bar are a pair ofcontactors engageable with the contact band portions of the metal endcaps when the starting bar is moved to the lamp starting position,thereby completing an electrical circuit leading from one resilientcontactor to the contact portion of one connector and to a first lampterminal, through one electrode and out a second lamp terminal along themetal cap through the connector to the starting bar, and through theother contact band and electrode to the other resilient contactor. Thuswhen the Starting bar is in the lamp Starting position, a circuit isprovided for a How of starting current through the two electrodesarranged in series circuit relation. When the starting operation iscompleted, the starting bar is returned to the inoperative position andthe lamp is maintained in operation by the potential difference providedby the connection of the two resilient contactors alone.

In accordance with another feature of the invention, and in order toreduce contact arcing and other undesirable phenomena caused by theengagement of the starting bar contactors with the contact bands, thereis provided a pair of normally open switch contacts associated with oneof the starting bar contactors. These switch contacts are not closeduntil the starting bar contactors are firmly in engagement with thecontact bands. Thus these switch contacts serve to make and break thestarting circuit, and any arcing occurs between these switch contacts,rather than between the contactors and the metal end caps of the lamp.

Although with the novel lamp starting arrangement of the presentinvention the lamp may be started during rotation, it may be desirableto stop the lamp during starting. Accordingly there is provided a novelarrangement for discontinuing the rotation of the lamp during starting.Mounted on the operating handle of the starting bar is a normally closedswitch connected to control the energization of the lamp drive motor. Asthe starting bar is moved from the inactive to the lamp startingposition, the switch engages a switch operator and is moved to its openposition, thus disconnecting the lamp drive motor and halting the lamp.The arrangement is such that the lamp is completely stopped before thelamp starting circuit is established.

Other objects and advantages and a better understanding of the inventionwill appear from the following detailed description in conjunction withthe drawings, in which:

FIG. 1 is a broken plan view of a direct contact printing machineconstructed in accordance with the invention, the top cover beingremoved more clearly to illustrate the machine;

FIG. 2 is an enlarged sectional view taken along the line 22 of FIG. 1,assuming FIG. 1 to show the complete structure;

FIG. 3 is a broken, enlarged elevational view, partly in section, of aportion of the apparatus of FIG. 1, particularly illustrating the lampconnecting and lamp starting structure;

FIG. 4 is a fragmentary sectional view taken along the line 4-4 of FIG.3;

FIG. 5 is a schematic diagram of a portion of the operating circuit ofthe machine of FIG. I, particularly illustrating the lamp operating andstarting circuitry; and

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 3illustrating a lamp terminal connector.

Referring now to the drawings and initially to FIGS. 1 and 2, there isillustrated a direct contact printing machine generally designated as 10and embodying the features of the present invention. The machine 10includes a housing generally designated as 12 within which there isrotatably mounted a fluorescent lamp 14. In order to provide anoperating potential across the lamp, the machine includes novelelectrical connecting apparatus generally designated as 16 forestablishing electrical connection with the two ends of the lamp. Inorder to start the fluorescent lamp at the beginning of a printingoperation, the machine additionally includes novel lamp startingstructure generally designated as 18.

Referring now in more detail to the construction of the machine 10, thehousing 12 includes a base 20 to which is removably secured a top cover22 for enclosing the internal structure of the machine and for limitingthe escape of light from the machine. Within the machine are mounted apair of side plates 23a and 2311. At the front of the machine there isprovided a paper feed and discharge opening 24 defined in part by a lipmember 26 including a feed table portion 26a. When it is desired to makea copy, a transparent or translucent graphic original sheet and aphotosensitive copy sheet or web are placed in interfacing orsuperimposed relation and fed along the feed table 26a into the machine.The superimposed sheets are guided between the sheet table 26a and aguiding assembly 28 to the region of the lamp 14.

In order fully to support and to rotate the lamp 14, the machineincludes spaced rollers 30, 32 and 34 extending between side plates 23aand 23b and around which are arranged a plurality of endless belts 36. Adrive motor 38 serves to rotate the roller 30 by means of a drivelinkage 40 and drive belt 42. Rotation of the roller 30 causes the belts36 to travel around a path over the roller 30 and the idler rollers 32and 34. In order to adjust the tension between the belts 36 and therollers 30, 32 and 34, there is provided a friction bar 44 over whichthe belts slide and which is mounted for movement in slots 46 in theside plates 23a and 23b (FIG. 2) to adjust the tension of the belts 36.

Along the path of the endless belts 36 is an included loop portion 36adisposed between the rollers 30 and 32. The lamp 14 includes anelongated cylindrical envelope 50 formed of glass or other transparentmaterial, the envelope being engaged by the loop portion 36a of thebelts 36. To further support the lamp envelope, the machine may includetwo pairs of friction wheels 51 mounted respectively at the ends of therollers 30 and 32. The friction wheels 51 serve to space the envelope 50of the lamp 14 from the rollers 30 and 32 in order to provide elongatedentrance and exit regions 52 and 53 at the regions where the belts 36engage and disengage the lamp 14. Thus, the support and the rotation ofthe lamp 14 is entirely accomplished by the belts 36, rollers 30, 32 and34, and friction wheels 51. Accordingly, it is not necessary for theelectrical connecting apparatus, described hereinafter, to provide anysupport for the lamp.

When superimposed copy and original sheets are fed between the feedtable 26 and guiding assembly 28 to the entrance region 52, the sheetsare held between the belts 36 and lamp envelope 50 and are transportedaround the lamp 14 to the exit region 53 and then out of the machine.During their travel around the lamp 14, the sheets are exposed to lightemanating from the lamp.

The housing 12 includes a control panel 12a (FIG. 1) supporting a powerswitch 54 and a direction control switch 55 for controlling thedirection of rotation of the lamp, whereby the direction may be reversedif desired. At the rear of the housing is an electrical connector 56 forsupplying power to the machine and an auxiliary outlet 57 for providingpower to a developer or other apparatus. An exposure control 58 isprovided for regulating the amount of light to which a copy sheet isexposed during printing by regulating the speed of operation of thedrive motor 38. For cooling the machine, a fan is mounted within a fancasing 59 communicating with a ventilation chamber 60 (FIG. 2), and isdriven by a fan motor 61.

Proceeding now to a description of the construction, operation andcontrol of the lamp 14, the lamp may comprise a standard type offluorescent lamp including the envelope 50, the inside of which may becoated with a suitable powdered phosphor material. Supported within theenvelope 50 are a pair of electrodes 62 and 63, one near each end of thelamp (FIGS. 3 and 5). A pair of terminals 64 and 65 are connected to thetwo ends of the electrode 62 and lead out from one end of the envelope50. Similarly, a pair of terminals 66 and 67 are connected to theelectrode 63 at the other end of the lamp. The lamp additionallyincludes a pair of metallic generally cup-shaped end caps 68 and 70, oneoverlying each end of the lamp. These caps include generally cylindricalportions 68a and 70a each extending for a short dislance over the outerwall of the envelope 50. As best appears in FIG. 3, the end caps 68 and70" are electrically connected respectively to the terminals 64 and 66,but are isolated from the terminals 65 and 67. Thus it can be seen thatthe electrodes 62 and 63 each have one end electrically communicatingwith a metallic end cap. The other end of each electrode communicateswith the other terminal 65 or 67, and is isolated from the end cap.

In the operation of the lamp 14, and as will readily be understood bythose skilled in the art, it is necessary first to preheat the lamp andthereafter to maintain an operating potential difference within thelamp. Preheating, or starting, of the lamp is accomplished by causingcurrent to flow through the lamp electrodes 62 and 63, heating them andcausing them to emit electrons. When sufficient electrons are released,the resistance of the gap between the electrodes is low enough to permitstriking an arc across the gap. Thereafter, the lamp is maintained inoperation by establishing a potential difference between the electrodes62 and 63.

In accordance with a feature of the invention, the novel electricalconnecting apparatus generally designated as 16 is provided.Accordingly, a pair of connectors 72 and 74 are frictionally mounted atthe ends of the lamp 14. These connectors are formed of an electricallyconductive material such as a suitable metal, and include openingsfrictionally engageable with the lamp terminals. The connector '74 isprovided with an insulating liner 76 surrounding the terminal 66, andwith an insulating shield 78 serving to isolate the connector 74 fromthe end cap 70. Similarly, the connector 72 includes a liner 80 and ashield 82 for isolating the body of the connector 72 from the end cap 68and from the terminal 64. However, the connectors 72 and 74 areelectrically connected respectively to the terminals 67 and 65.

The connectors 72 and 74 include central openings within which arefrictionally held shank portions 84a and 86a of a pair of button typecontact members 84 and 86, the contacts 84 and 86 being positionedsubstantially along the axis of the lamp 14. It will be appreciated thatthe contacts 84 and 86 are in electrical communication respectively withthe electrodes 62 and 63 by means of the connectors 72 and 74 and theterminals 65 and 67, whereas the terminals 64 and 66 and the end caps 68and 70 are electrically connected to the other ends of the electrodes6-2 and 63.

In order to establish a potential difference between the electrodes 58and 59, there are provided a pair of resilient leaf spring typecontactors $8 and 90, one disposed at each end of the lamp 14. Thecontactors 88 and 90' are secured to the base 20 by means of fasteners92, but are insulated therefrom by means of insulating material 94. Thecontactors 88 and 90 are connected respectively to a pair of terminalbrackets 96 and 98 to which are secured a pair of conductors 100 and 101leading to a power supply including first and second conventionalballasts 102 and 103 (FIGS. 1 and As most clearly appears in FIG. 3, theresilient connectors 88 and 90 bear against the contact members 84 and86 thereby establishing electrical connections via the connectors 72 and74 with the spaced electrodes 62 and 63, whereby a lamp operatingpotential difference is maintained between the spaced lamp electrodes.It will be appreciated that this electrical connection is maintainedwhen the lamp is stationary or rotating, and therefore the lamp iscapable of operating during rotation. Furthermore, an extremely simpleand compact arrangement is provided in the connectors 72 and 74 andcontactors 88 and 90 by which this operating connection may be made.

In accordance with a further feature of the invention, the novel lampstarting structure generally designated as 18 is provided. The structure18 serves to complete an electrical starting circuit for the lamp 14thereby allowing a starting current to travel through the electrodes 62and 63. The starting structure 18 includes a starting bar 104 formed ofconductive material and journaled for rotation in the side plates 23aand 23b by means of insulating bushings 106. The bar is rotatablebetween an inactive position, as illustrated in the drawings, and a lampstarting position by means of an operating handle 108 which extends fromthe bar 104 to a convenient position at the front of the machine nearthe control panel 12a.

In order to provide a path for current to flow between the end caps 68and 70, a pair of contactors 110 and 112 are mounted at spaced positionsalong the bar 104 for registry respectively with the cylindricalportions 68a and 70a of the end caps 68 and 70. The cylindrical portions68a and 70a serve as contact bands for the contactors 110 and 112, andwhen the starting bar 104 is rotated by means of the handle 108 to thelamp starting position, a lamp starting circuit is established. Thisstarting circuit comprises a path including the resilient leaf springcontactor 88, the button contact 84, the connector 72, terminal 65,electrode 62, terminal 64, end cap 68, contactor 110, along the starting'bar 104 to the contactor 112, the end cap 70, the terminal 66, theelectrode 63, the terminal 67, the connector 74, button contact 86, andthe other resilient leaf spring contactor 90. In order to start the lamp14, the starting bar 104 is maintained in the lamp starting position fora short period during which the resistance of the gap between theelectrodes 62 and 63 is reduced as discussed above. Thereafter thestarting bar 104 is returned to the illustrated inactive position andthe lamp is maintained in operation by the above described connectingapparatus 16.

In order to avoid arcing between the contactors 110 and 112 and the endcaps 68 and 70, the lamp starting structure 13 includes a pair of switchcontacts 114a and 11422 carried respectively by the contactor 112 and bya switch arm 116 mounted in electrically conducting relation to thestarting bar 104 (FIG. 4). Thus as the start ing bar 104 is moved towardthe lamp starting position, the contactors 110 and 112 engage the endcaps 68 and 70 while the switch contacts 114a and 11412 remain in theirnormally open position. As the starting bar 104 is moved the rest of theway to the lamp starting position, the contacts 114a and 114b close,thus completing the lamp starting circuit. Thus any arcing is restrictedto the region between the contacts 114a and 11411.

It will be appreciated that due to the simple arrangement of thecontactors 110 and 112 on the starting bar 104 and the use of the endcaps 68 and 70 as band type contacts, the starting circuit may beestablished in any angular position of the lamp 14. Furthermore, ifdesired, the starting circuit could be established while the lamp isrotating. However, it is desirable to stop the rotation of the lamp 14while the lamp is being started. Accordingly, and in accordance with afurther feature of the invention, there is provided a switch 118 fordisconnecting the power to the drive motor and speed control portions ofthe machine during starting (FIGS. 1, 4 and 5). The switch 118 comprisesa normally closed snap acting type switch fastened to the operatinghandle 108. When the starting bar 104 is rotated to the startingposition by means of the handle 108, an actuating lever 120 associatedwith the switch 118 engages a switch operating bracket 122 fastened tothe side plate 23b whereby the switch is moved to the open circuitcondition and the drive motor is disconnected, thus stopping therotation of the lamp 14. After the lamp is started, and the operatinghandle 108 returned to the inactive position, the switch actuating lever120 moves away from the bracket 122 and the switch again closeswhereupon the drive motor is energized and proceeds to rotate the lamp14.

Although the present invention has been described with reference to aspecific illustrative embodiment thereof, it should be understood thatnumerous other modifications and embodiments can be devised by thoseskilled in the 7 art that will fall within the spirit and the scope ofthe invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. In an apparatus for exposing superimposed copy and original sheets bypassing said superimposed sheets over the surface of an illuminatingsource, the combination comprising:

a lamp having a cylindrical envelope,

a pair of spaced apart contactors fixedly mounted to a base support,

terminal means extending axially from the ends of said lamp,

support means acting independently of said contactors for supporting theenvelope between said contractors with its axis of rotation lying in aplane substantially parallel to said base member and being in electricalcontact therewith,

spacer means for spacing and supporting the envelope with respect tosaid support means providing entry Way means and exit means at theregions where said support means engage and disengage said envelope,said contactor including conductive biasing elements to accommodate theindependent movement of the lamp in said support and spacer means inorder to maintain continuous electrical contact of the lamp duringrotation.

2. The combination of claim 1 additionally comprising:

an electrode within said envelope connected to said terminal;

an additional terminal at said end of the envelope connected to saidelectrode, said connector being engageable with said additionalterminal; and

means associated with said connector for electrically isolating saidadditional terminal from said contact portion. 3. The combination ofclaim 2 additionally comprising: a conductive cap member fixed to saidend of said envelope, said cap member being electrically connected tosaid additional terminal; and

conductive means selectively engageable with said cap member forcompleting an energizing circuit for said electrode between saidconductive means and said contactor.

4. In apparatus for exposing superimposed original and copy sheets tolight from a vapor lamp having a cylindrical envelope, the combinationcomprising:

means engageable with the envelope of the lamp for supporting the lamp;

means for rotating the lamp;

first and second cylindrical contact bands surrounding the envelope, onenear each end of the lamp;

first and second additional contacts, one associated with each end ofthe lamp and located substantially along the axis of the lamp;

first and second electrodes within the lamp envelope;

means for connecting each electrode between one of said cylindricalcontact bands and one of said additional contacts;

first and second contactor means disposed near the ends of the lamp andengageable with said additional contacts for establishing a differencein potential between said electrodes to operate the lamp; and

means for starting the lamp including third and fourth contactorsselectively engageable with said first and second contact bands forcompleting a circuit allowing current to flow through said electrodes.

5. The combination of claim 4 wherein said starting means comprises: aconductive member mounted for movement between an inactive position anda lamp starting position, said third and fourth contactors being mountedon said member for engagement with said contact bands in the lampstarting position of the member for connecting said electrodes in aseries circuit relation with one another.

6. The combination of claim 5 additionally comprising: switch contactsassociated with said starting means movable from an open condition to aclosed condition when said member reaches the lamp starting position tointerconnect the third and fourth connectors after the third and fourthconnectors engage the contact bands.

7. The combination of claim 4 wherein said connecting means comprises:

a pair of terminals at each end of the lamp, each pair being connectedto one of said electrodes and a first terminal of each pair beingconnected to one of said contact bands;

first and second connectors mounted respectively on the pair ofterminals at each end of the lamp, each connector supporting one of saidadditional contacts and including means for electrically interconnectingthe additional contact and the second of the pair of terminals; and

insulating means associated with each connector for isolating theadditional contact from the first terminal of the pair.

8. The combination of claim 7 additionally comprising: a metal end capat each end of the envelope, said contact bands comprising integralportions of said end caps.

9. The combination of claim 5 additionally comprising means forpreventing rotation of the lamp when said conductive member is moved tosaid lamp starting position.

10. The combination of claim 9 wherein said rotation preventing meanscomprises a switch connected to control said lamp rotating means andoperable to deenergize said lamp rotating means in response to movementof said conductive member to said lamp starting position.

References Cited UNITED STATES PATENTS 9/1949 Young 2405l.11 3/ 9 Ellis240-49 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,351,752 November 7, 1967 Joseph Hruby It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 5, line 35, for "67 and 65" read 65 and 67 11ne 47, for "58 and59" read 62 and 63 column 7, lines 15 and 16, for "contractors" readcontactors Signed and sealed this 12th day of November 1968.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

1. IN AN APPARATUS FOR EXPOSING SUPERIMPOSED COPY AND ORIGINAL SHEETS BYPASSING SAID SUPERIMPOSED SHEETS OVER THE SURFACE OF AN ILLUMINATINGSOURCE, THE COMBINATION COMPRISING: A LAMP HAVING A CYLINDRICALENVELOPE, A PAIR OF SPACED APART CONTACTORS FIXEDLY MOUNTED TO A BASESUPPORT, TERMINAL MEANS EXTENDING AXIALLY FROM THE ENDS OF SAID LAMP,SUPPORT MEANS ACTING INDEPENDENTLY OF SAID CONTACTORS FOR SUPPORTING THEENVELOPE BETWEEN SAID CONTRACTORS WITH ITS AXIS OF ROTATION LYING IN APLANE SUBSTANTIALLY PARALLEL TO SAID BASE MEMBER AND BEING IN ELECTRICALCONTACT THEREWITH, SPACER MEANS FOR SPACING AND SUPPORTING THE ENVELOPEWITH RESPECT TO SAID SUPPORT MEANS PROVIDING ENTRY WAY MEANS AND EXITMEANS AT THE REGIONS WHERE SAID SUPPORT MEANS ENGAGE AND DISENGAGE SAIDENVELOPE, SAID CONTRACTOR INCLUDING CONDUCTIVE BIASING ELEMENTS TOACCOMMODATE THE INDEPENDENT MOVEMENT OF THE LAMP IN SAID SUPPORT ANDSPACER MEANS IN ORDER TO MAINTAIN CONTINUOUS ELECTRICAL CONTACT OF THELAMP DURING ROTATION.